Fix security vulnerabilities. Add logging

Dockerfile

@@ -1,6 +1,11 @@
 # Use Python 3.11 slim image
 FROM python:3.11-slim
 
+# Ensure Python output is sent straight to stdout/stderr (no buffering),
+# which is required for logs to appear in `docker logs`.
+ENV PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1
+
 # Set working directory
 WORKDIR /app
 
@@ -17,8 +22,8 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY src/ ./src/
 COPY data/ ./data/
 
-# Create data directory if it doesn't exist
-RUN mkdir -p data
+# Create data and log directories if they don't exist
+RUN mkdir -p data logs
 
 # Expose port
 EXPOSE $APP_PORT